Tesla batteries: Not so easy to kill.

Earlier this week, a tech blogger caused some consternation for Tesla Motors by claiming the batteries on the company’s pricey, plug-in sports cars could easily be ruined.

Just leave the car unplugged for a short period of time, in some hypothetical cases as short as a week, and the batteries would lose their charge, blogger Michael DeGusta wrote. Once fully depleted, the batteries could no longer be recharged and would need to be replaced, costing the car owners at least $32,000.

Photo: Jonathan Alcorn, Bloomberg

Citing information from an unnamed Tesla service manager, DeGusta claimed that at least five Tesla customers had inadvertently killed their batteries and turned their flashy cars into expensive “bricks.” He gave details on four of those five cases, again without naming names.

On Friday, Tesla fired back, criticizing the blogger for spreading “irrational fear.” The Roadster does need to be plugged in, Tesla noted in a post on the company’s blog. But the battery takes longer to discharge that DeGusta indicated. And the car repeatedly warns its driver whenever the charge dips too low (below 5 percent).

According to the company, the battery in the original model of the Tesla Roadster would take two months to completely discharge, assuming it had a 50 percent charge when it was unplugged. And Tesla’s batteries have improved since then. The battery in the Model S sedan, scheduled to go on sale later this year, would take a year to approach full discharge under the same circumstances, according to the company. Read Tesla’s full blog post here.

Meanwhile, some other bloggers have gone after DeGusta, saying he’s a business partner of one of the unnamed drivers who accidentally “bricked” a Tesla.